Any unjust law can be made unworkable by organised public non-cooperation and defiance, as has been shown by so many struggles throughout history. One of the most recent in the UK was the successful mass non-payment of the Government's Poll Tax, leading to its abolition.
Claim:
Abortion and euthanasia are thus crimes which no human law can claim to legitimize. There is no obligation in conscience to obey such laws; instead there is a grave and clear obligation to oppose them by conscientious objection. From the very beginnings of the Church, the apostolic preaching reminded Christians of their duty to obey legitimately constituted public authorities (cf. Rom 13:1-7; 1 Pet 2:13-14), but at the same time it firmly warned that "we must obey God rather than men" (Acts 5:29). In the Old Testament, precisely in regard to threats against life, we find a significant example of resistance to the unjust command of those in authority. After Pharaoh ordered the killing of all newborn males, the Hebrew midwives refused. "They did not do as the king of Egypt commanded them, but let the male children live" (Ex 1:17). But the ultimate reason for their action should be noted: "the midwives feared God" (ibid.). It is precisely from obedience to God-to whom alone is due that fear which is acknowledgment of his absolute sovereignty-that the strength and the courage to resist unjust human laws are born. It is the strength and the courage of those prepared even to be imprisoned or put to the sword, in the certainty that this is what makes for "the endurance and faith of the saints" (Rev 13:10). In the case of an intrinsically unjust law, such as a law permitting abortion or euthanasia, it is therefore never licit to obey it, or to "take part in a propaganda campaign in favour of such a law, or vote for it". The passing of unjust laws often raises difficult problems of conscience for morally upright people with regard to the issue of cooperation, since they have a right to demand not to be forced to take part in morally evil actions. Sometimes the choices which have to be made are difficult; they may require the sacrifice of prestigious professional positions or the relinquishing of reasonable hopes of career advancement. In other cases, it can happen that carrying out certain actions, which are provided for by legislation that overall is unjust, but which in themselves are indifferent, or even positive, can serve to protect human lives under threat. There may be reason to fear, however, that willingness to carry out such actions will not only cause scandal and weaken the necessary opposition to attacks on life, but will gradually lead to further capitulation to a mentality of permissiveness. (Papal Encyclical, Evangelium Vitae, 25 March 1995).